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High resolution Space Imagery for the Assessment of Urban Vulnerable Areas
2nd Japan-Peru Workshop on Earthquake Disaster Mitigation
Lima - Peru, March 13, 2007
Miguel Estrada
Universidad Nacional de Ingeniería
Kyoto University
ウニベルシダヅ ナシオナル デ インヘニエリア
What we need to Identify?
Vulnerable locations in urban areas to be prepared for a disaster or retrofit the existing buildings located in dangerous places.
Is it Possible to use Satellite Images?
Cover a vast area of land
There is historical imagery
Periodical acquisition (4th dimension)
Spectral Information (5th dimension)
Various satellites on orbit
Reasonable price?
Ikonos Satellite
Commercial SatelliteResolution of 4m and 1m4 spectral bands1 panchromatic band1 scene 165 km2
Short return periodCapacity of obliqued vision
Satellite Image of Lima(12.1x14.6km aprox.)
PhD. Ing. Miguel Estrada Mendoza
Sensors
Each material on the Earth shows a characteristic way to reflect or emit electromagnetic energy.The sensors onboard of satellites can “feel” the strength of this reflected of emitted energy.
PhD. Ing. Miguel Estrada Mendoza
Since satellite imagery are made of Numbers (digital numbers)
PhD. Ing. Miguel Estrada Mendoza
Using Spectral InformationBanda 1
Banda 2
Banda 3
Banda 4
PhD. Ing. Miguel Estrada Mendoza
How To Process the Information
Conversion A/Dde analog imagery
Conversion D/DSatellite images
Digital Information (images)
Radiometric Correction
Geometric Correction
Transformation Classification
Analog output Digital database
Image Input
Pre-processing
Output Image
Processing
ProblemDefinition
Mejoramiento de imágenesTrue True ColorColor ~ 4~ 4.0.0mm
Bands 3, 2 and 1 (RGB)Bands 3, 2 and 1 (RGB)Improved Improved Color Color ImageImagePanchromatic Panchromatic ImageImage 11..00mm
Mejoramiento de imágenes
Phase 1:Identification
Phase 2:Video
Phase 3:Video
Phase 4:Video
Phase5: Video
Spectral Analysis
Pseudo Infrared Colour Image
Normalized Differenced Vegetation Index
),(),(
),(),(j)(i,
jiji
jiji
RNIR
RNIRNDVI
+
−=
Cluster Analysis
Middle Resolution Satellite Image
Conclusions
Satellite imagery can give a general idea about the social and economic distribution in an urban area.Social and economic condition could provide an idea on the quality of housings.Spectral analysis can be used to automate the assessment and evaluation of urban areas.Further analysis on the roof´s spectral response could be give further details.Middle resolution satellite images also could investigated for the urban inventory issues.